2bku: Difference between revisions
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==Overview== | ==Overview== | ||
Nuclear protein import is mediated mainly by the transport factor | Nuclear protein import is mediated mainly by the transport factor importin-beta that binds cytoplasmic cargo, most often via the importin-alpha adaptor, and then transports it through nuclear pore complexes. This active transport is driven by disassembly of the import complex by nuclear RanGTP. The switch I and II loops of Ran change conformation with nucleotide state, and regulate its interactions with nuclear trafficking components. Importin-beta consists of 19 HEAT repeats that are based on a pair of antiparallel alpha-helices (referred to as the A- and B-helices). The HEAT repeats stack to yield two C-shaped arches, linked together to form a helicoidal molecule that has considerable conformational flexibility. Here we present the structure of full-length yeast importin-beta (Kap95p or karyopherin-beta) complexed with RanGTP, which provides a basis for understanding the crucial cargo-release step of nuclear import. We identify a key interaction site where the RanGTP switch I loop binds to the carboxy-terminal arch of Kap95p. This interaction produces a change in helicoidal pitch that locks Kap95p in a conformation that cannot bind importin-alpha or cargo. We suggest an allosteric mechanism for nuclear import complex disassembly by RanGTP. | ||
==About this Structure== | ==About this Structure== | ||
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[[Category: Protein complex]] | [[Category: Protein complex]] | ||
[[Category: Saccharomyces cerevisiae]] | [[Category: Saccharomyces cerevisiae]] | ||
[[Category: Lee, S | [[Category: Lee, S J.]] | ||
[[Category: Liu, S | [[Category: Liu, S M.]] | ||
[[Category: Matsuura, Y.]] | [[Category: Matsuura, Y.]] | ||
[[Category: Stewart, M.]] | [[Category: Stewart, M.]] | ||
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[[Category: rangtp]] | [[Category: rangtp]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:38:50 2008'' | ||
Revision as of 17:38, 21 February 2008
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KAP95P:RANGTP COMPLEX
OverviewOverview
Nuclear protein import is mediated mainly by the transport factor importin-beta that binds cytoplasmic cargo, most often via the importin-alpha adaptor, and then transports it through nuclear pore complexes. This active transport is driven by disassembly of the import complex by nuclear RanGTP. The switch I and II loops of Ran change conformation with nucleotide state, and regulate its interactions with nuclear trafficking components. Importin-beta consists of 19 HEAT repeats that are based on a pair of antiparallel alpha-helices (referred to as the A- and B-helices). The HEAT repeats stack to yield two C-shaped arches, linked together to form a helicoidal molecule that has considerable conformational flexibility. Here we present the structure of full-length yeast importin-beta (Kap95p or karyopherin-beta) complexed with RanGTP, which provides a basis for understanding the crucial cargo-release step of nuclear import. We identify a key interaction site where the RanGTP switch I loop binds to the carboxy-terminal arch of Kap95p. This interaction produces a change in helicoidal pitch that locks Kap95p in a conformation that cannot bind importin-alpha or cargo. We suggest an allosteric mechanism for nuclear import complex disassembly by RanGTP.
About this StructureAbout this Structure
2BKU is a Protein complex structure of sequences from Canis lupus familiaris and Saccharomyces cerevisiae with and as ligands. The following page contains interesting information on the relation of 2BKU with [Importins]. Known structural/functional Site: . Full crystallographic information is available from OCA.
ReferenceReference
Structural basis for nuclear import complex dissociation by RanGTP., Lee SJ, Matsuura Y, Liu SM, Stewart M, Nature. 2005 Jun 2;435(7042):693-6. Epub 2005 May 1. PMID:15864302
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